Carburetor



Sept. 28, 192e.

S. CHAPPEL Filed May 1.. 1924 .GNN

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S. CHAPPEL CARBURETOR Filed May 1, 1924 2 Sheets-Sheet 2 H U A @new www i NW lT l .BNN .M\m% J uw m mm mm. m mn QW Sx mv d @n mw QN. ww @W mm.

'Syntrax crm., or ATrLEBoRo, MASSACHUSETTS."

CARBURETOR.

Application filed-May 1, 1924. Serial No. 710,471.

The principal objects of this invention are to provide an efficient and economical compensating mixture of gasoline and air over the whole range of speeds of the engine, and particularly for slow engine speeds or the average driving speed; to provide a new form of Venturi tube or passage through which the air to be carburetted is caused to flow and part of it is caused to be divided out of the main stream and have a turning motion resulting in an increased vacuum and a more intimate mixture of fuel and air, increasing the power presumably by the elimination of condensation of the heavier particles of gasoline adhering to the walls of the carburetor, as well as the reduc- 'tion of the air velocity around the fu'el nozzle topromote economy; to provide an accelerating device for causing the carburetor to respond quickly to the requirements of the engine by suddenly increasing the supply of fuel when the throttle is opened and at the same time shutting off the air vent leading to the fuel nozzle; to provide a compensating device for causing a very lean mixture of fuel and air to be introduced, when running along at a uniform speed, and the throttle is closed or nearly so and vice versa; and to provide a choke valve in the hot air passage leading to the mixing chamber for starting the cold motor and regulating the quality of the mixture in cold weather. f

yThe invention involves certain details of construction of the parts above mentioned and combinations with each other. Further objects and advantages of the-invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in which Fi 1 is a longitudinal sectional view of a car uretor constructed in accordance with this invention on the line 1-1 of Fig. 2;

Fig. 2 is a transverse sectional -view on the line 2-2 of Fig. 1;

gig. 3 is an elevation of the Venturi tube; an A Fig. 4 is a sectional view of the same on the line 4-4 of Fig. 3.

I haveshown the invention as receiving its fuel from la iioat chamber 9 formed integrally with the casing 10 of the carburetor. This float chamber is provided with the usual needle valve 11 operated by a oat 12 for controlling the feed of liquid fuel, as for example, gasoline, into the lioat chamber 9 through an inlet 13.l The details of the mechanism for transmitting motion of the lioat 12 to the valve 11 will not be described in detail as they are shown as of an ordinary conventional kind.

This float chamber 9 has a space 59 at one side and also at one side of the carburetor casing 10 which of course is filled with gasoline up to the level maintained in the main body of the oat chamber 9. This space is provided with a port 15 delivering the gasoline into a channel 16 and controlled by a needle valve 17 which is adapted to be adjusted by hand to maintain the feed as may be desired at this point. This channel 16 communicates with a passage 17 a extending vertically in the casing and communicating with an idling tube 24 in an accelerating well 18. The passage 17a is restricted to prevent too rapid discharge. It also communicates through a channel 19 witha chamber 2O in the casing 10 in which well is provided a plug 21. This compensating well supplies the gasoline through a uniform vertical tube 22 directly into the center of the Venturi tube 23.

It is sufficient to say here that the gasoline passes up through an idling tube 24 in the well 18 when idling to an air port 25 which is controlled by a needle valve 26 adjusted by hand and air is taken from the outlet passage to the intake manifoldwat aqpoint just short of the end of the Venturi tube 23. The air and fuel also are free to pass up into a chamber 27 which is provided with a plug 28 having a port through it discharging directly through the wall into the outlet in the vicinity of the throttle valve 30. This chamber is closed in by a screw plug 29.

The accelerating device is connected so that on the opening of the throttle valve 30 by turning its shaft 31, a lever on that shaft operates through a'llink 33 and arm 34 constituting part of a bell crank. The other end of this bell crank presses down on the top of a plunger 35 and depresses it. This plunger is provided with two tandem pistons 36 and 37 spaced apart to form an air-space and located in an accelerator well 38 in the casing communicating through a port 40 with the -well 18.. In the well 38 there are two air inlets 39 and 49. The inlet 49 is about twice as large as the inlet 39 so that when the piston 36 is depressed enough'to cover the inlet 49 it cuts ofi' about twothirds of the air passing through the passage 4() into the well 18. The lower piston 37 rests on a spring 41 which normally holds the pistons up so that the lower piston 37 is above the normal level of gasoline in the carburetor. However the well is filled up to the bottom of the piston. This spring is located in the bottom of the well 38 which communicates through a passage 42 with the passage 17 a filled with gasoline. lVhen the plunger is depressed the piston 37 of course comes down in opposition to the spring and forces the reserve supply of gasoline under it through the passages 42, 17 and 19 up the tube 22 and out into the engine. At the same time the piston 36 comes down and cuts oft' two thirds of the air supply through theV passage so that the mixture forced into the engine in this way is not only suddenly sprayed into it but is much' richer, due to the fact that only a small amount of air is introduced with it.

It will be observed that the same action i affects the introduction fof air through a passage 44 through the vwell 18 into the compensating well 43. Under ordinary circumstances air is free to iiow through this passage 44 and through ports 45 into the central tube or nozzle 22. lVhen the accelerator is depressed the flow is increased suddenly so that the engine can be started more easily when cold. The fuel nozzle and tube 22 constitute two separate parts forming one unit. In the top of the compensating well 43 is provided one air duct 45 discharging into the gasoline stream in the tube 22, and in the bottom there are three or four ports supplied by the same number of air ducts 46 when the gasoline is drained out of the well 43. As stated these air ducts, although arranged at dierent levels, discharge into'the gasoline stream in one plane at the bottom of the compensating tube for the purpose of thoroughly7` breaking up the gasoline into a foam which vaporizes more readily.

On account of the accelerating device the carburetor will quickly respond to the requirements of the engine. The gasoline is thoroughly broken up into an emulsion so that it will vaporize very readily and it is to'be noticed that the air pressure supplied to it is controlled by the accelerating device. When the engine is running at idling speeds and speeds below ten miles per hour the air ducts 46 are sealed with gasoline. When the speed increases by opening the throttle valve, thereby increasing the suction around the main nozzle 22, gasoline discharges into the tube 22 from the main passage and the four or tive auxiliary passageways or air ducts 46. As the gasoline level lowers in the compensating well the upper air duct is uncovered. This permits a small amount of air to enter into the main gasoline stream,

thereby reducing the flow. This operation repeats itself as the speed of the motor is increased, uncovering the remaining air ducts, each of which supplies a portion of air at different speeds and cuts down the gasoline supply.

On account ot thev atmospheric pressure in the compensating well being controlled by the accelerating device a strong flow of air at slow engine speed is provided, thus promoting economy. The reduced flow of air at higher speeds increases the power and flexibility. This latter operation takes place when the throttle valve is about half open.

An important feature of this invention is the Venturi tube 23 through which the mixture of gas and outside air are introduced into the engine. This Venturi tube, as indicated in Figs. 6 and 7 especially, is grooved externally with a number of grooves 51 arranged at an angle of 20 to the vertical and all slanting in the same way, of course, on the outside of the tube, These grooves are located on the exterior where the tube tits into the outlet passage 52 and form inclined passageways outside the tube for the air to pass through as the mixture comes through the center. The air coming through these grooves is caused to turn in a clockwise direction, resulting in an increased vacuum and a more intimate mixture of gas and air. They also reduce the air velocity around the fuel jet, thus promoting the greatest economy..v These grooves, being close to the wall, also seem to eliminate any condensation of the heavier particles of gasoline which adhere to the walls of the carburetor which would cause a direct loss of power. The Venturi tube extends down into the hot air passage instead of being located entirely in the mixing chamber. This permits of the use of a long Venturi tube with a short carburetor.

In operation when the throttle is closed the pistons 36 and 37 are in the upper position and are maintained in this position by the spring 41. The air ducts 46 are sealed with gasoline. The main fuel'nozzle 22 does not discharge as the air velocity is too low. The space below the piston 37, being filled with gasoline from the float chamber, the gasoline is forced by the depression of the accelerator on the opening of the throttle in any way to flow out through 42, 17, 19 and 20 to the main nozzle 22. At the same time the upper piston 36 shuts o about twothirds of the compensating air flowing through 40, 18, 44 and 43 to be mixed with the gasoline and going out through the main jet. As the gasoline lowers in the compensating well the first air duct 45 becomes uncovered which permits a small amount of air to enter the main gasoline stream thereby reducing the flow. This operation repeats itself as speed of motor is increased uncover- This results in a strong pick-up. At the` same time the flow of gasoline through the tube 24 and plug 28 is suddenly increased, thus further assisting in starting the engine. The usual choke valve 50 is shown operated in substantially the usual manner.

As has been stated the air which passes to the compensating well through the pas sages 40, 18 and 44 compensates for the different engine speeds by causing a very lean mixture to be introduced when the throttle is closed to promote economy but to increaser the richness of the mixture when the sudden demand is felt. It will b e seen that the mixture supplied to the engine is varied so as t0' provide for eliiciency and economy over the whole range of speeds of the engine, and particularly at slow engine speeds or the average driving speed. On account of the construction of the Venturi tube a turbulence above it is caused which mixes the gasoline and air more intimately. This prevents the heavier particles of gasoline from adhering to the walls of the carburetor and, as the air is decreased at low engine speeds, the economy of this part of the device is improved.

It will be seen therefore that this carburetor produces high power because of the low resistance from the short length of carburetor; it also provides a high mileage with economy because the quality ot' the mixture is made lean under ordinary driving speeds; the practicability oi' using a lean mixture is increased by the high capacity of the Venturi tube, and by the action of the pick-up device and the mixture can be enriched suddenly when desired. 'lbe engine will be capable of strong idling because'the mixture is maintained at a very low minimum quality. The mixture does not get weak even at speeds below the ordinary speeds. The operation of the carburetor is uniform because the function of regulating the air and gasoline mixture is formed by orifices which are located in the right position and are directl and uniform in their action. There is little or nothing to get out of order and the action of the device is positive.

Although I have illustrated and described only a single form of the invention I am aware of the fact that modifications can be made therein by any person skilled in the art without departing from the scope of the' invention as expressed in the claims, Therefore I do not wish to be limited in these respects, but what I do claim is l. In a carburetor, the combination with a float chamber, of a compensating well having a plug across it and an accelerating well connected therewith and mounted in a position in which liquid fuel from the float chamber will normally rise to the same level in said wells, the carburetor having an outlet for mixed fuel and air, and a port communicatin with said compensating well below the p ug for delivering fuel into said well, means in the compensating well for forcing fuel through said port and means for introducing air into the compensating well above the liquid fuel therein and above the plug, said forcing means in said accelerating well also controlling the supply of air to the compensating well. i'

2. In a carburetor, the combination with a float chamber, of a compensating well and an accelerating well connected therewith, said compensating well havinga. vertical tube therein having a ort through which the air can enter the tu e below the level of the liquid, two plungers in the accelerating well positively connected together, one located at the level of liquid therein and the other in position to control the supply of air to the compensating well, and a spring for holding said plungers up out of .o erative position, whereby when the two p ungers are depressed, a small amount of liquid fuel will be forced into said compensating well by the lowerplunger and the upper plunger will partially cut oli' the supply of air to said port.

In testimony whereof he has hereunto affixed his signature.

SYDNEY cI-IAPPEL. 

